Many wireless terminals include two or more transmit antennas. Each antenna may include a separate transmit chain and power amplifier, where different signals are transmitted from the different antennas. Different signals may be transmitted from the different antennas due to the technology used (e.g., Multiple Input Multiple Output Antennas (MIMO)), to provide transmit diversity, for up-link spatial multiplexing, and the like. In such cases, the signals transmitted from the multiple antennas may be different due to pre-coding, although the data stream before the pre-coding may be the same.
One problem that can arise in multiple antenna wireless systems is signal coupling between antennas. For example, a portion of the transmitted signal from one antenna may be captured by another antenna. The “transmit leakage” from one antenna to another can cause problems if the transmit chains include power detection components. Power detection components may be used to determine the transmitted power output at each antenna, for example. The accuracy of power detection associated with an antenna may be reduced due to the coupling of stray or unwanted signals onto elements of the antenna, such as from an adjacent antenna, for example.